Sync our homegrown SysInfo replacement with the one in Chrome base.

test/base-unittests/sys-info-unittest.cc

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/base/sys-info.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace v8 {
+namespace base {
+
+TEST(SysInfoTest, NumberOfProcessors) {
+  EXPECT_LT(0, SysInfo::NumberOfProcessors());
+}
+
+
+TEST(SysInfoTest, AmountOfPhysicalMemory) {
+  EXPECT_LT(0, SysInfo::AmountOfPhysicalMemory());
+}
+
+
+TEST(SysInfoTest, AmountOfVirtualMemory) {
+  EXPECT_LE(0, SysInfo::AmountOfVirtualMemory());
+}
+
+}  // namespace base
+}  // namespace v8